According to the American Council on Exercise, the plank exercise is one of the top ten abdominal exercises. This exercise is a great way to flatten your stomach, strengthen your core and improve the endurance of your back and stomach muscles. By strengthening your core, you will strengthen your hips and pelvic floor. Having a strong core, stomach and back muscles will lead to improved posture and may help prevent injuries. The only equipment that you need for the plank exercise is your own body and enough floor space to lie down on.